There are persistent rumors that the main ingredient in JB Weld is magic. This two-part epoxy that you would normally find on a shelf next to your basic 5-minute epoxy, Titebond, various cyanoacrylates, and Gorilla glue is somehow different. Stories of ‘some guy’ in the Yukon using JB Weld on a cracked engine block abound. These stories are of course met with skepticism.
Now, finally, we have evidence you can use JB Weld to fix an engine. [Project Farm] over on YouTube gave it the ultimate test: he took the cylinder head off a lawnmower, took a grinder to the head, and patched the hole with JB Weld. The head had good compression, and the engine actually ran for 20 minutes before the test was concluded.
If this were a test of a field repair, it would be a test of an extremely crappy field repair. [Project Farm] made no attempt to ensure the piston didn’t make contact with the blob of JB Weld, and in fact, there was some slight knocking from the piston tapping against a blob of epoxy. Still, this repair worked.
While this serves as proof of the feasibility of repairing an engine block with JB Weld, there is one ultimate test of JB Weld epoxy: build an engine out of it. For years, I’ve been casting my leftover JB Weld into a small square plastic container. In a few more years, I’ll have a block of JB Weld ‘stock’, large enough to machine the parts for a small (.049 cc) glow engine, like what you would find in ye olde tymie model planes and cars. Will it work? I have no idea, but now I can’t wait to find out.
Stirling engines are really cool machines, invented by Reverend Dr. Robert Stirling in 1816 to rival the steam engine, they are one of the most efficient engines ever conceived. Building one is a very rewarding experience, but it has a certain level of difficulty. However, [Attila Blade]’s version of a free-piston type Stirling engine is simple enough to be built in a matter of minutes.
To build the engine you only need a test tube, steel wool, a latex glove, an O ring and some wire. The construction is straightforward as you can see in the video. The whole engine rocks on the wire frame which also makes it different to most other Stirling engines that you can watch on the net. The free piston is just one type of several possible configurations for a Stirling. The most common one, is the beta type, usually made with soda cans, but it is much more difficult to build than [Attila Blade]’s engine.
This is definitely a fun project that you may want to try, and is also a great way to learn thermodynamics concepts. Even if you don’t build this particular version, there are many other possibilities using mainly household items, or you can also check the very interesting history behind the Stirling engine.
We’ve had our eye on [Greg Zumwalt]. He’s been working on some very clever 3D-printed mechanisms and his latest prototype is an air engine for a toy car. You can supply the air for the single cylinder with a compressor, or by blowing into it, but attaching an inflated balloon makes the system self-contained.
Last week we saw the prototype of the engine by itself, and wondered if this had enough power to drive a little train engine. We were almost right as here it is powering the front wheels of a little car.
This isn’t [Greg’s] first rodeo. He’s been working on self-contained locomotion for a while now. Shown here is his spring-driven car which you pull backwards to load the spring. It’s a common feature in toys, and very neat to see with the included 3D-printed spring hidden inside of the widest gear.
That print looks spectacular, but the balloon-powered prototype tickles our fancy quite a bit more. Make sure you have your sound on when you watch the video after the break. It’s the chuga-chuga that puts this one over the top. [Greg] hasn’t yet posted files so you can print your own (it’s still a prototype) but browse the rest of his designs as you wait — they’re numerous and will bring an even bigger smile to your face. Remember that domino-laying LEGO bot [Matthias Wandel] built a few years back? [Greg] has a printable model for it!
You can make a lot of stuff out of paper, but a single-stroke engine model less than an inch across? That’s a new one, courtesy of Russian hacker [Aliaksei Zholner], who built a quite remarkable model of a single-stroke engine out of paper (in Russian, translated version via Google Translate). Measuring less than an inch across, it is driven by compressed air and accurately models the rotary action of a single-stroke engine, where a piston in the cylinder drives a flywheel that creates the engine cycle.
The creator has managed to run it at up to about 60 revolutions per second, or about 3600rpm. That’s an impressive speed for a few bits of paper and glue, and there is even an input restrictor that can control the airflow that drives the model. We’ve featured some interesting paper creations before, such as this papercraft robot and a Strandbeest, but this one is a step beyond. [Aliaksei] has also made the plans and template for this available, so those with steady hands can go ahead and try to make their own.
The modern motorcycle represents the pinnacle of over a century of refinement in design and manufacture of its every component. A modest outlay will secure you a machine capable of three figure speeds with impeccable handling, breathtaking acceleration and stopping power, that somehow seems also to possess bulletproof reliability that will take it to a hundred thousand miles of faithful transport.
At the dawn of the internal combustion engine age it was a different matter. Machines were little more than bicycles with rudimentary engines attached, brakes and tyres were barely capable of doing the job demanded of them, and the early motorcyclists were a hardy and daring breed.
You might think that this article would now head into retrotechtacular territory with a nostalgic look at an early motorcycle, but instead its subject has a much more recent origin. We happened upon [Buddfab]’s contemporary build of a 1905-era motorcycle, and we think it’s a bike you’d all like to see.
The bike itself is a faithful reproduction of a typical Edwardian machine. It has a modified bicycle frame with a belt drive and springer front forks. That’s all very impressive, but the engine is a masterpiece, crafting a more modern parts bin into something resembling a 1905 original. He’s taken the cylinder, piston, and half a cylinder head from an aircooled VW flat four and mated it with the crankshaft of a 125cc Honda, welding the two connecting rods together to join German and Japanese parts. With a custom-made crankcase, Lucas points, and the carburetor from a British Seagull outboard motor it both looks and sounds like an original, though we’d expect it to be significantly more reliable.
You can see videos of both bike and engine below the break, as he takes it for a spin through American suburbia. Sadly we’ll never see it passed to the definitive writer on early motorcycles for an expert view, but it would fool us completely.
With a welder and a bunch of scrap, you can build just about anything that moves. Want a dune buggy? That’s just some tube and a pipe bender. Need a water pump? You might need a grinder. A small tractor? Just find some big knobby tires in a junkyard. Of course, the one thing left out of all these builds is a small motor, preferably one that can run on everything from kerosene to used cooking oil. This is the problem [Shane] is tackling for his entry to the 2016 Hackaday Prize. It’s an Open Source Two-Stroke Diesel Engine that’s easy for anyone to build and has minimal moving parts.
[Shane]’s engine is based on the Junkers Jumo 205 motor, a highly successful aircraft engine first produced in the early 1930s and continued production through World War II. This is a weird engine, with two opposed pistons in one cylinder that come very close to slamming together. It’s a great design for aircraft engines due to it’s lightweight construction. And the simplicity of the system lends itself easily to wartime field maintenance.
The Jumo 205 was a monstrous 12-piston, 6-cylinder engine, but for [Shane]’s first attempt, he’s scaling the design down to a 50cc motor with the intent of scaling the design up to 125cc and 250cc. So far, [Shane] has about 30 hours of simple CAD work behind him and a ton of high-level FEA work ahead of him. Then [Shane] will actually need to build a prototype.
This is actually [Shane]’s second entry to the Hackaday Prize with this idea. Last year, he threw his hat into the ring with the same idea, but building a working diesel power plant is a lot of work. Too much for one man-year, certainly, so we can’t wait to see the progress [Shane] makes this year.
Electric cars are all the rage lately, but let’s not forget about the old standby – internal combustion. The modern internal combustion engine is a marvel of engineering. Today’s engines and surrounding systems have better power, greater fuel economy, and lower emissions than anything that has come before. Centuries’ worth of engineering hours have gone into improving every aspect of the engine – with one notable exception. No automotive manufacturer has been able to eliminate the engine’s camshaft in a piston powered-production vehicle. The irony here is that camless engines are relatively easy to build. The average hacker could modify a small four-stroke engine for camless operation in their workshop. While it wouldn’t be a practical device, it would be a great test bed for experimentation and learning.
Suck, Squeeze, Bang, Blow
A multi-cylinder gasoline engine is a complex dance. Hundreds of parts must move in synchronicity. Valves open and close, injectors mist fuel, spark plugs fire, and pistons move up and down. All follow the four-stroke “Intake, Compression, Combustion, Exhaust” Otto cycle. The camshaft controls much of this by opening and closing the engine’s spring-loaded intake and exhaust valves. Lobes on the shaft press on tappets which then move the valve stems and the valves themselves. The camshaft itself is driven at half the speed of the crankshaft through timing gears, chains, or a belt. Some valve trains are relatively simple – such as overhead cam engines. Others, such as the cam-in-block design, are more complex, with pushrods, rockers, and other parts required to translate the movement of the cam lobe to movement at the valve.
Exactly when, and how fast a valve opens is determined by the profile of the cam lobe. Auto racing and performance enthusiasts often change camshafts to those with more aggressive profiles and different timing offsets depending on the engine’s requirements. Everything comes at a cost though. A camshaft machined for maximum power generally won’t idle well and will make the engine harder to start. Too aggressive a lobe profile can lead to valve float, where the valves never fully seat at high RPM.
Engine manufacturers have spent years working around the limitations of the camshaft. The results are myriad proprietary solutions. Honda has VTEC, short for Variable Valve Timing and Lift Electronic Control. Toyota has VVT-i. BMW has VANOS, Ford has VCT. All these systems provide ways to adjust the valve action to some degree. VANOS works by allowing the camshaft to slightly rotate a few degrees relative to its normal timing, similar to moving a tooth or two on the timing chain. While these systems do work, they tend to be mechanically complex, and expensive to repair.
The simple solution would be to go with a camless engine. This would mean eliminating the camshaft, timing belt, and most of the associated hardware. Solenoids or hydraulic actuators open and close the valves in an infinitely variable number of ways. Valves can even be held open indefinitely, effectively shutting down a cylinder when max power isn’t necessary.
So why aren’t we all driving camless engines? There are a few reasons. The advantages of camless engines to camshaft engines are analogous to the advantages of electronic fuel injection (EFI) vs carburetors. At the core, a fuel injector is a solenoid controlled valve. The fuel pump provides constant pressure. The engine control unit (ECU) fires the injectors at just the right time to inject fuel into the cylinders.The computer also leaves the valves open long enough so that the right amount of fuel is injected for the current throttle position. Electronically this is very similar to what would be required for a camless engine. So what gives?
Hackers in their 30’s and beyond will remember that until the late 1970’s and early 1980’s, the carburetor was king. Companies had been experimenting with EFI since the 1950’s. The system didn’t become mainstream until the stiff pollution laws of the 70’s came into effect. Making a clean, fuel-efficient carbureted engine was possible, but there were so many mechanical and electronic actuators required that the EFI was a better alternative. So the laws of the 70’s effectively regulated carburetors out of existence. We’re looking at much the same thing with camless engines. What’s missing are the regulations to force the issue.
All the big manufacturers have experimented with the camless concept. The best effort to date has been from Freevalve, a subsidiary of Koenigsegg. They have a prototype engine running in a Saab. LaunchPoint Technologies have uploaded videos showing some impressive actuator designs LaunchPoint is working with voice coils, the same technology which moves the heads in your hard drive.
None of this means that you can’t have a camless engine now – companies like Wärtsilä and Man have engines commercially available. However, these are giant diesel engines used to drive large ships or generate power. Not exactly what you’d want to put in a your subcompact car! For the hacker set, the best way to get your hands on a camless engine today is to hack one yourself.
Ladies and gentlemen, start hack your engines!
Simple, single-cylinder camless engines are relatively easy to build. Start with a four stroke overhead valve engine from a snowblower, scooter, or the like. Make sure the engine is a non-interference model. This means that it is physically impossible for the valves to crash into the pistons. Add a power source and some solenoids. From there it’s just a matter of creating a control system. Examples are all over the internet. [Sukhjit Singh Banga] built this engine as part of a college project. The control system is a mechanical wheel with electric contacts, similar to a distributor cap and rotor system. [bbaldwin1987’s] Camless Engine Capstone project at West Virginia University uses a microcontroller to operate the solenoids. Note that this project uses two solenoids – one to open and one to close the valve. The engine doesn’t need to rely on a spring for closure. [Brian Miller] also built a camless engine for college, in this case Brigham Young University Idaho Camless Engine. [Brian’s] engine uses hall effect sensors on the original camshaft to fire the solenoids. This route is an excellent stepping stone before making the jump to full electronic control.
It wouldn’t take much work to expand these projects to a multi-cylinder engine. All we’re waiting for is the right hacker to take up the challenge!